Apparatus for controlling endless belts



Sept., 30, 1958 J. J. MAclEJowsKl APPARATUS FOR CONTROLLING ENDLEss BELTS Filed OOC. 6, 1955 Inventor John cf Maciejowslfz' APPARATUS FOR CONTRLLING ENDLESS BELTS .lohn J. Maciejowski, Wenham, Mass., assignor to United Shoe Machinery Corporation, Flemington, N. J., a corporation of New Jersey Applicationoctoher 6, 1955,*Serial No. 538,902

8 Claims. (Cl. 19g- 202) This invention relates generally tothe control of traveling endless belts and particularly to apparatus for causing a belt which is subject to undesirable lateral displacement to travel in a predetermined path. More particularly, the invention relates to conveyor systems having endless belts which are subject to lateral displacement due to an uneven absorption of moisture from work pieces conveyed by such belts. The preferred embodiment f the invention 4is herein illustrated in its application to a conveyor system, such as that embodied in an automatic leather stacking machiney of the type described in United StatesLetters Patent No. 2,777,564, granted January l5, 1957, on an application led in the name of George E. Russell, lr. It is to be understood, however, that the present invention is not limited in its utility to leather stacking machines nor to transferring leather work pieces.

In conveying work pieces by means of endless belts it is necessary, or at least desirable, that the conveying belts travel in' a straight path with little or no lateral displacement in order properly to control the movement of conveyed work pieces. In yautomatic stacking machines of the type illustrated in the above-mentioned patent a plurality of long, narrow belts are used to convey work pieces upwardly along an inclined frame and downwardly along a depending and oscillating delivery arm `to dis-` charge the work pieces in a work receiving zone beneath the delivery arm. Means are provided for oscillating the delivery arm in proper timed relationship to the passage of the midfportion of the work pieces so that they will be properly balanced in most instances on'a horse. For

detecting thepassage jof a work piece along the'main frame to determine the mid-portion thereof a number of work detectingdiingers are arranged to lie in relatively narrow spaces between Vthe conveying belts. Accordingly,

any substantial lateral displacement of said belts would damage lor at least hinder the eectiveness of the detect ing lingers. v 4

lu conveyingworkl pieces by means yof long, endless belts it has y beenra problem to insure that such belts travel properly on theirrcarryingpnlleysrwithina small rangek of lateral displacement.` To aid in belt tracking crowned4 pulleys have long beenl utilized for carrying the belts whereby theoretically `the larger diameter of the crown4 causes the'v center portionA Iof the belt to travel at a higher speed thanthe margins thereofand in this manner a component of forces develops which must be neutralized by having equal-portions of the belt on each side of the crown. work pieces that the use of crowned pulleyswill'cause the'conveyorI belts'to ytrack within the narrow range of lateral displacement necessary for use in automatic leather stacking machines of the type disclosed in the above-mentioned patent. However, when damp or wet work pieces are conveyed by the same method, the conveying belts absorb moisture from lthe work pieces in an uneven manner. The uneven absorption Vof moisture causes the belts to shrink unevenly and either run 0E the Applicant'h'as found in the conveying of dryV rice Patented Sept.- 30, 1958 carrying pulleys or be displaced laterally to an unaccept-y able degree.y vIt was found inthe course of investigation thatit was either impractical or not economical to utilize belts of a material that would be unaected by moisture. However, when a belt deviates lfrom its normal path due to uneven absorption of moisture, if water is applied to the belt margin having the least moisture, then the shrinkagev tensions inthe belt become equalized and the belt returns toits normal pathl It was discovered 'that' such anexpedient was most effective when the belts were carried by pulleys Vin which the `center portion of the" pulley is 0f less diameter than the two edges thereoff Accordingly, an yobject of the inventionris to providemeans forselectivelyapplying water to either margin ofy a belt yfor controlling lateral displacement in either of" two directions whereby the belt is caused to track within' a narrow range of lateral displacement. It is another object of this invention to provide the combination 'of' pulleys' having a smaller diameter in the center thereof for carrying said '-belt, together'with automatic means for' wetting Veither margin of a belt to control lateraldisv placement thereof.

For Vthe purpose'in'view the' machine herein shown is provided with `a water pipe which vextends transversely"V above the return runs of thel conveying belts. A plurality of holes Vprovided in the pipe allows water' tov drop 'freely by both margins' of each' belt without wetting said belts when they are centered' on 'their Vcarrying pulleys. lt-

one of` the lbelts absorbs moisture unevenly fromV work pieces being' conveyed, thereby causing the belt to drift laterally int the direction ofthe driest margin of the belt, thaise-called dry margin intercepts the flow of water adjacenttheretoand becomes' wet, thusy causing that 'side' 0f the belt to shrinkf andreturn to its normal position'. To increase theetectiveness of Ithe centering-action of the belt, the beltl'carryi'ng pulleys arevso shaped thatthe ""offthe'pulley is of lesser diameter than" companying'drawings and thereafter pointed out inthe' claims;

in the drawings,y

Fig:y l is'a view-"intleft-hand lelevation of the machineA to `whichthe"inve1`1'tion'is Aherein shown as'applied;

Fig.-v 2 VYis a section substantially on line II II vof Fig. 3, and

figi 'is a fragmentary plan View on anenlarged scaler4 oflaiiporti'on of rtliemachinewith parts broken away to illustratethe invention.

The 'automatic leather stackingm'achine shownin Figivl is oftliebasic4 typedisclsed'in United States Letters namefsfof -Paul Morgan," Arthur R. Abbott,v and lohn-` I. Maciejfowski.

The' machine is mounted -on aroller" base 10 from which'supportsfand 14 extend upwardly to 'carry side frames 16 (onlyion'e' of which-is seen) ion* either side* ofthe machine'.I An upwardlyiinclin'ed-isup# port leirtend's'between' the frames 16; Adelivery 20 is pivotall'y'secured' at the upp'er endof Saidisid .frames and comprises ktwo framev members 22 'between which a memberdextends in1v order'toprovide rigidity for the" delivery arm. Aiud motor 26 acting through' suitable linkage providesf means for oscillatingthevv dellr llvery arm 20'through workdelivering 1n`^otionsasrcon`y trolled by a cam-controlled mechanism C and-in' amanener fully described-inthe'above mentioned PatentiNo. 2,737,390.

A1 lower conveyor 40 passes around a roll 42 journaled at the lower end of the side frames 16 and has aworleport 18, passing around a pivot roll 44 journaled at the to the'roll 42. i

A'second, QI ilppergconyeyoru passes around aroll 52 mountedabovegthe frames" 16 toyc'ommence avwork'- engaging vrun incontiguous relation with the work-engagf' ing run ot the lower conveyor 4 0. VThe `work-engaging` run tot the yupper conveyorl50 thusl extends upwardly along the support 18, around the rpivot ro l l 44, downi wardly along the delivery arrn` 20, `and .aroundga -rollL 54 to commence'its return runto. the lowerrollSZ.

The upper and lower conveyorsS() and 40 each comprises a seriesgofendless tapes 41` spaced ,across the supe port 18. .The spacingkbetween thetapes lfacilitates the detection of work pieces, and also ithas been found that relatively narrow tapes provide ease'of manufacture and assembly, as well as having better-.tracking V characteristics. A motoryM drives the lower conveyor 40 Vthrough a pulley 7 0 securedl `tothe roll 42j. No vinterconnection is made vbetween the rolls of the upper and lower con-y veyor vsystems as ,it hasl been found that'theffriction vbetween the contiguous runs of these twoconveyors is suficient for ,driving Athe upperY conveyor.

Detector fingers 72 of the typedescribed Vin United.' StatesLetters Patent No. 2,743,924, granted'May l, 1956,V onfan .application iiledin the names ,of RichardA Elliott and EdmundSfLee, III, extend lbetween thejtapes of theupper, andlower conveyors Sil/and 40 Vand enter recesses Yin thesupport 18..r The fingers 7-2 arepivotally mounted'on a framework74fabovethe support 18 and are arranged in two stations so' that theywill'bel displaced as a work piece yis conveyed up the support 18y and there by selectively detect the passage of theleading and trailt ingedges of the work piece. `The detection made by the fingers 72 Vis transmitted to a. timing mechanisrnTv of the type also described in the last-mentioned patentwhich actuates the cam controlled .mechanism C to cause oscillation' ofV the delivery arm 2G.v TheV upperand'lower conveyors are'driven constantly by .the'motorfM, and'in the operation of the machine leather work pieces ,are

introduced at the lower end of the conveyor 40 either .i

directly froma through feed leather treatingmachine. or by meansv of, some intermediate transferI `means.V The work pieces are carried upwardly between the conveyors 40 and 50, and as their leading and trailing edges pass the detector lingers 72, electrical impulses are transmitted to thetiming mechanism T which initiate a computing# cycle within they timing mechanism.' The worlt pieces are carried varound thel pivotroll 44 and dischargedfrom the. lower end of thevdelivery arm 20.l The timing mech-y anism IV actuates Vthe cam controlled mechanism vC ata time dependent upon the work piece length asdetermined4A by theimpulses transmitted in responsejto displacement of the lfingers 72. The cam controlled mechanism C,

thereupon causes pressurized Liiuid to be introduced into one end of theV uid motor 26 dependent upon ythe initial" position of the delivery arm 20.V The delivery arm is thus oscillatedlthrough its linkagejsystem in proper time relationship lso that each work piece will beproperly placedk in a work-receiving zone.` The mode` of.` operation ofthe cam controlled mechanism C` and timing mechanismT formv no'part` of the present invention.

details of.theirconstruction.V` A v f As previously mentioned, any `substantiallaterfal dis-1 placement of the conveyor tapes would result in a -serious interference with the detecting Yfingers 72. Accordingly, to aid in Vpreventing lateral Vdrifting' of theV vtapesf'filthe clear the workingelement's *of the'machineasit passes Reference is'-y therefore made to theabove-rnentioned patentsffor the i necked portions 4S. `The setting up opposing forces inthe tape which must be balanced or equalized by having equa1 portions of thatape on each side of the necked portion 48; Y

' 10 Further to prevent lateral drifting of the tapes, the

machine is provided with a water pipe.56 `secured tothe side frames 16 in a suitable manner. `(The pipeis connected to a source of water (not shown) and extends.V transversely above the returnrun of the conveyor 40. A

number of pairs of small holes SS'are provided inthe bottom of the pipe, the holes of each-pair being -spaced apart a distance slightly greater than the width of the ,individualtapes 41. Thus, when the tapes are tracking properly on the roller .42, water emitting from .the holes '20 58 will not strikev the tapes but willpass freely .throughjthev spaces between the tapes in. a manner illustrated in 'l Fig 2. However, in conveyingdamp or `wet work pieces some tapesV absorb moisture unevenly sothat one margin i thereof tends to shrink more 'than the other, causingxthe i wet margin to drift toward the center-necked portion 48 of the rollerV due to its increasedV tension.' As thetape beef 1 gins to drift laterally the drier margin ofV the tape inter-c cepts a stream of water emitting lfr'om oneof the holes' "'58 causing that margin to shrink and counteract theuno even forces set up in the other margin. As`alresult,n"'to .al equalize the opposing forces in the.tapethe^tape must s return to its original position onrthe roller 'with equal-wV portions of the tape running along either side of thel: A

necked'portion 48, To'accommodatethe-water whichis ,35 constantly flowing from the holes l58 in the pipe 561af tray 59` is mounted on the machine in a position underlying theV tapes 41 and the pipe 5.6 so that the water-flowing Vfrom the 'holes 58 may be collectedandconductedifl awaytrom the work'area.

Having thus describedmy invention, what 1 claim aslnew and desire to secure `by Letters Patent of the United` j.

States is:

1. In apparatus'for controlling endless traveling belts-v subject to lateralv deviations froina desired normal path,

said belt causes said belt toreturnt'o sai'd'path.-

2. Inapparatus for controlling endless travelingbelts subject` to lateralzdeviations from a desired normal'path',-V

thecombinationy of pulleys for carryingY abelt, vand means for applying a shrinking mediumY to one margin lofsaidf Abelt when increased Vtension of the' other "margin 'thereof l causes' said belt to deviate'from a predeterminednornal' path vwhereby the tensions, of bothy margins Vbecome4 l equalized, causing said belt to return to said path;l

n 3. In apparatus for controlling jendless traveling belts "subject vto lateral deviations from 'a desired normal"'pathjfY v60 the combination ofpulleys forcarryinga belt, said pulleys` being so shapedl that lthe marginal portionsiof saidfvibelt'jv carried therebyV are under greater tension than the center;

portion of sadVbeIt, and means'forfapplyinga L"medium to 'a margin of said belt. Whensai'd beltdeviates from a predetermined normal path'whereby. th'e'increasedf,y tension of said margin of said,belt^ca ses,said -belt to rev turnrto saidfpath.

4. In apparatus for controllingiendless traveling I Je'lts subject tor lateral deviations from a desirednormal path,

the combination of pulleysl Vfor carrying a belt,j andmeans forapplying water to one margin of said belt when .said belt deviates from a predetermined normal lpath whereby; 1: the tension of said margin increases, causingsaidbelttov roller 42 v(Fig. 2f) has providedV 'thereon'a' plurality -of`f`75 return'to'said path.

tapes are so carried by the l roller that the margins .of..each.. tape run non vportionsmof l 5. In apparatus for controlling endless traveling belts subject to lateral deviations from a desired normal path, the combination of pulleys for carrying a belt, said pulleys being so shaped that the marginal portions of said belt carried thereby are under greater tension than the center portion of said belt, and means for applying water to one margin of said belt when said belt deviates from a predetermined normal path whereby the tension of said margin increases to cause said belt to return to said path.

6. In apparatus for controlling endless traveling belts subject to lateral deviations from a desired normal path, the combination of pulleys for carrying a belt, and a pipe extending transversely above said belt, said pipe being connected to a source of water and having holes therein spaced apart a distance slightly greater than the width of said belt, said holes being so arranged that jets of water emitting from said holes fall freely by both margins of said belt When said `belt is traveling in a predetermined normal path but also so arranged that a jet of water will be intercepted by one or the other margin of said belt when said belt deviates laterally in either of two directions.

7. In apparatus for controlling endless traveling belts subject to lateral deviations from a desired normal path, the combination of pulleys for carrying ya belt, said pulleys being so shaped that the marginal portions of said belt carried thereby are under greater tension than the center portion of said belt, and a pipe extending transversely above said belt, said pipe being connected to a source of water and having holes therein spaced apart a distance slightly greater than the width of said belt, said holes being so arranged that jets of water emitting from said holes fall freely by both margins of said belt when said belt is traveling in a predetermined normal path but also so arranged that a jet of water will be intercepted by one or the other margin of said belt when said belt deviates laterally in either of two directions.

8. In apparatus for conveying work pieces by means of endless belts which are subject to lateral displacement due to an uneven absorption of moisture, the combination of pulleys for carrying said belts, each of said pulleys being so shaped that the marginal portions of each of said belts being carried thereby are under greater tension than the center portion of each belt, means for driving said pulleys, and a pipe extending transversely above said belts, said pipe being connected to a source of water and having holes therein, said holes being so arranged that jets of water emitting from said holes fall freely by both margins of each of said belts when said belts are traveling in predetermined normal paths but also so arranged that a jet of Water will be intercepted by a margin of any of said belts when any of said belts deviates laterally in either of two directions.

References Cited in the iile of this patent UNITED STATES PATENTS 169,573 Parr Nov, 2, 1875 878,815 Martin Feb. 11, 1908 2,330,923 Robins Oct. 5, 1943 Krotz Aug. 8, 1944 

